The present invention relates generally to a method and apparatus for improving tap water from urban water supplies and more particularly concerns a method for reducing the quantities of free chlorine and chlorinated hydrocarbons which exist in the water. Drinking water processed according to the present invention has very noticeably improved taste characteristics.
It is long time practice to add chlorine to urban water supplies. Such chlorine is added for its germicidal effects. While the addition of chlorine has varied definite benefits, there has been much recent concern over the adverse side effects of such chlorine usage. First of all, chlorine causes an allergic reaction in many people. Secondly, it has been found that, even in dilute aqueous systems, purine and pyrimidine bases commonly found in natural water systems may react with chlorine to form compounds that are mutagenic. There is a high probability that compounds that are mutagenic are also carcinogenic. The chlorine may thus also react with purines existing in the body tissue itself causing cancer of different parts of the body. Free chlorine can also react with coffee, tea, cola and other common drinks which contain caffeine to produce chlorinated caffeine which is proven to be carcinogenic according to the Ames tests. Furthermore, chlorine and chlorinated hydrocarbons give water an adverse taste and removal of these products results in substantial improvement in the taste quality of the water.
While other germicidal additives, such as iodine, have been considered to replace chlorine, it is highly likely that chlorine will be added to urban water supplies for many years. It is thus highly desirable to remove chlorine and chlorinated hydrocarbons from these water supplies prior to drinking the water. Also, as a practical matter, any apparatus for removing the chlorine and chlorinated hydrocarbons from the water must be highly economical in order to invite widespread usage.
In the past, various types of in-line filters containing various activated carbon particles have been used. These in-line filters are subject to many disadvantages and may, in fact, prove to be dangerous. For the most part, these in-line filters are ineffective since water passing through the filters is under substantial pressure and contacts the activated carbon for only a few seconds, much less than the time applicant has found necessary to effectively remove chlorine and chlorinated hydrocarbons. Moreover, these in-line filters are subject to bacteria buildup. The plumbing work which is necessary to replace many of the in-line filters further complicates the matter and encourages use of filters beyond their useful lives. When used after bacteria buildup, water may actually be contaminated when passed through such in-line filters.
Applicant has previously proposed an effective method and apparatus for removing certain chemicals from drinking water which is disclosed in U.S. Pat. No. 4,211,649. The present invention represents an improvement over that method and apparatus which is more economical and has greater simplicity.
It is thus an object of the present invention to provide a method and apparatus for removing chlorine, chlorinated hydrocarbons and other organic compounds from drinking water in a highly economical manner.
It is a further object of the present invention to provide a method and apparatus for removing chlorine, chlorinated hydrocarbons and other organic compounds from drinking water with minimal danger of bacterial buildup.